Conventionally, a variety of motorcycles have been sold and put to practical use (see, for example, Japanese Utility Model Laid-open No. Sho 58-181687 (FIG. 2)).
FIG. 24 of the present application is a copy of FIG. 2 of Japanese Utility Model Laid-open No. Sho 58-181687. As shown in FIG. 24, a small-type motorcycle has been known in which luggage can be mounted on the upper side of an upper frame 20 extending forwards from a seat 2, an auxiliary frame is extended forwards from the upper side of the upper frame 20 to be a front carrier 12, and accessories such as a head light 18 are attached to the front carrier 12.
In such a known construction as that shown in FIG. 24, in a medium- or larger-type motorcycle, the vehicle body extends in the front-rear direction, so that it is necessary to strengthen the vehicle body frame, in order to ensure that luggage can be mounted on the upper frame. In a low floor type vehicle represented by a motor scooter with a straddle portion, also, it is desired to provide the straddle portion with a luggage mount portion. On the other hand, customers demand a variety of frame shapes.
Accordingly, it is an object of the present invention to provide a motorcycle and an improved frame structure for a motorized vehicle. More particularly, it is an object of the present invention to provide a motorcycle and frame having a strengthened vehicle body frame in order to enhance the luggage mounting performance at a straddle portion and which can be made in a variety of main frame section shapes.